Description: This 1.6 Å structure of BtDyP from the gut bacterium B. thetaiotaomicron is among the first crystal structures of a dye-decolorizing peroxidase (DyP), revealing a novel two-domain α+β ferredoxin-like fold with a conserved heme-binding motif. The hexameric assembly structure established the structural foundations for this new family of heme-dependent peroxidases with applications in bioremediation and biotechnology.